Unfortunately, with the way this employer has the match set up, we can't front load easily - the employer match is calculated each pay period, so if you didn't contribute that pay period, no match! It's a bit of a dance to max out contributions exactly on the last paycheck.
From my understanding, your employer is not handling the match correctly if that is how they are doing it. I was worried about matching issues as well when researching if I could do front-loading or not. Are you sure that they don't match, or would they do a "true up" later in the year wherein you get your 3% match? Here is what the IRS has to say about this:
"If an employee starts or stops salary reduction contributions in the middle of the year, can I make my 3% match based only on the compensation earned during the period they actually contributed?
No, you must base your SIMPLE IRA plan employer matching contribution on the employee’s entire calendar-year compensation, regardless of when the employee starts or stops contributing during the year. The maximum matching contribution is always 3% of the employees’ compensation for the entire calendar year. Matching contributions may be made on a per-pay-period basis, or by the due date of the employer’s tax return (including extensions).
Example: Bob’s annual salary is $50,000 and he starts contributing to his employer’s SIMPLE IRA plan on September 1. He contributes $1,536 through December 31. Bob’s employer must match Bob’s contributions up to 3% of Bob’s calendar-year compensation, or $1,500 (3% of $50,000). It doesn’t matter that Bob only contributed to the plan during the last 4 months of the calendar year.
Example: John earns $60,000 a year. He made a salary reduction contribution of $12,000 to his employer’s SIMPLE IRA plan from January 1 to September 30. John’s employer is required to match John’s contribution up to 3% of his entire calendar-year compensation or $1,800 (3% of $60,000), even though John stopped contributing to the plan on September 30.
Example: Joe’s annual salary is $70,000 and he contributed 1% of his compensation, or $700, to his employer’s SIMPLE IRA plan. Joe’s employer must make a matching contribution of $700 because the employer is only required to match the amount Joe actually contributes during the year up to a maximum of 3% of his calendar-year compensation."
Source:
https://www.irs.gov/retirement-plans/simple-ira-plan-faqs-contributions